The present invention relates to a device for grinding the head of a valve, especially of an internal-combustion engine.
The present invention is described and explained by reference to the valves of thermal combustion engines, especially internal-combustion engines. It must be understood, however, that the scope of the present invention should not be limited to this technical sector, because many other members having the shape of a valve or described as such have to be machined or ground in order to fit a complementary sealingly closing seat; as an example of another technical sector to which the present invention can apply, that of sealing sluices may be mentioned.
By "grinding" is meant machining by the removal of metal, whether a machining with a cutting tool by the removal of a metal chip or a machining of the milling type by the removal of metal particles. Such machining can be carried out both for finishing, that is to say directly after the manufacture of a valve stem, and for repair or reconditioning, that is to say for shaping the head of a worn valve in terms of profile and dimensions to those of a new or ground valve seat.
By "device" are meant appliances or installations which can range from a lightweight tool of the bench-tool type in a repair workshop to a much heavier machine of the machine-tool type, as used in factories for the series production of thermal engines.
In general terms, and as shown more particularly in FIG. 1, a valve 1 comprises a stem 1a of cylindrical or tubular shape and a head 1b of a shape widened continuously with the stem. This head 1a comprises a front or forward plane face 1g perpendicular to the valve axis and opposite the stem end or tail 1c. The face to be machined or ground is the rear face 1f, for example according to a conical surface 1i, concentric relative to the axis of the valve or axis of the stem 1a.